Pressure Washer Modifications


Author: Tom Eddleman


Revised: August 03, 2005


After trial and error this works. Nicholas Mazza ordered the parts and modified a pressure washer with them.

Most sandcarvers quickly discover the advantages of using a pressure washer for developing photo resist.  If you get a low cost Karcher or the equivalent pressure washer it will run somewhere around $100, but the wand that comes with it is way too long to washout resist with, so modifications have to be made.

From Northern Tools:

here's a list of what you need:

The Karcher pressure washers have a 22mm male thread outlet

The Northern Hose P/N 32090 hose ($16.99) has 22mm female thread on both ends

One end connects to the pressure washer outlet and the other to a

Northern P/N 22321 adapter ($4.99) that is 22mm male thread on one end and 3/8 NPT female thread on the other end.

The female thread part of the adapter screws over the Northern P/N 2296 nipple ($2.99) that is 3/8 NPT male thread on both ends.

That nipple screws into the Northern P/N 227770 ($14.99) pistol grip gun inlet.

 A 1/4"x 3" NPT nipple (hardware store) screws into the outlet on the gun and a Northern P/N 2234 quick coupler ($5.99) screws onto that nipple. A Northern P/N 230340 ($6.99) 40 degree nozzle connects with that quick coupler.

Northern         Hose                             P/N 32090  ($16.99)

                        adapter                         P/N 22321   ($4.99) 

                        nipple                            P/N 2296    ($2.99)

                        pistol grip gun              P/N 227770 ($14.99)

                        quick coupler               P/N 2234    ($5.99)

                        40 degree nozzle        P/N 230340  ($6.99)

Hardware Store: nipple 1/4"x 3" NPT

This should get you going. Home Depot, Lowe's, etc. may have the best deal on the pressure washer.

One of the reasons that pressure washers come with a long wand is because it's harder to inject water into your body with a long wand. That can send you to the hospital. If you make this modification to your pressure washer be very careful. It's very dangerous.

On operating temperature: do not operate the washer above 105F, since the Buna N seals will be destroyed at higher temperatures.  You can guesstimate the temperature, or buy a Radio Shack remote thermometer with probe for less than $20.  The fancier models also include humidity readout with memory, for not much more.









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